1. Field of the Invention
The present invention relates to a production plan apparatus that creates a production plan that is used to manufacture and deliver a requested quantity of products by a delivery date, e.g., an end of a month that is a predetermined deadline.
2. Description of the Related Art
A manufacturing process of a product is constituted of respective steps, e.g., processing, assembling, testing and others. These steps are made up of one or more production lines. These production lines are constituted of a plurality of processes. In these processes, an operation based on a production facility or manpower is carried out.
In a manufacturing plant, each product is manufactured based on a warehousing request set based on a request from a customer. The warehousing request is constituted of items of a requested product, a quantity, and a warehousing requested date. The manufacturing plant must take off each product from a final step to meet a warehousing requested date of each warehousing request.
In the manufacturing plant, a takeoff objective (delivery objective) at each step to take off a product from the final step is set in accordance with a warehousing request. The takeoff objective is constituted of items, a quantity, and a takeoff date of a requested product. The takeoff objective is calculated by, e.g., tracking back a lead time from a warehousing requested date to the next and subsequent steps based on computer arithmetic processing.
A warehousing objective or a takeoff objective in which a quantity of a product for each takeoff schedule is a product determined for the reason that a customer has been already informed of a delivery date is called a delivery request. According to the delivery request, a product must be taken off to avoid a delay on a priority base.
A production plan of a product corresponding to a predetermined item is created in accordance with each step in order to meet a takeoff objective. The production plan for each of these steps is calculated based on a lead time or throughput of the next and subsequent steps, e.g., throughput of each production line at each step, a lead time at each step for each item, or a takeoff objective from a customer by computer arithmetic processing. Further, the production plane at each step is represented in the form of a list of, e.g., each production quantity for each item of a product in each day at each step. This list is displayed in a display or the like.
The production plane obtained by the computer arithmetic processing may include delay of a takeoff quantity from a takeoff objective because of, e.g., throughput of a production line at each step or a restriction in a lead time and a takeoff objective period.
An operator of the production plan sees a list of the production plan displayed in the display to confirm a degree of delay of the production plan from the takeoff objective. After confirming the degree of delay in the production plan, the operator of the production plan considers a set throughput of the production line, a margin of the lead time, and others to adjust the production plane to recover from the delay with respect to the takeoff objective as much as possible. At this time, the operator of the production plan must also consider a degree of delay with respect to the takeoff objective based on, e.g., throughput at the next step. The degree of delay is a degree of an influence on takeoff from the final step based on a warehousing request.
A technology concerning the production plan is disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2002-373011. Jpn. Pat. Appln. KOKAI Publication No. 2002-373011 discloses a technology of judging whether production performance satisfies a production objective and outputting a countermeasure if the production objective is not satisfied.